i7-8700k power draw

[MattyG344]

So I just finished an i7-8700k/GTX 1080 ti build and have been monitoring temps and the like and noticed that HWmonitor is telling me that my CPU is only drawing around 25w at idle. I ran the Asus stress test on it and even at full load, the power draw never went above 50w.

This is going to be a kind of "explain it like I'm 5" situation because I don't understand CPU power draw at all, but is that bad? I'm seeing other people with draws WAY higher than that and I don't know if it's an indicator of something wrong or it's just how it is and I should carry on.

 

[TJ Hooker]

I don't trust software power reporting, only accurate way to measure power is with a power meter of some sort.

If you're worried your CPU is underperforming, run a benchmark (e.g. cinebench) and compare it to other results.

 

[volkgren]

That's normal to see with software such as HWInfo and typical loads.

Intel specified the i7-8700K has a 95W TDP.

They also state: "Thermal Design Power (TDP) represents the average power, in watts, the processor dissipates when operating at Base Frequency with all cores active under an Intel-defined, high-complexity workload. Refer to Datasheet for thermal solution requirements."
https://ark.intel.com/products/126684/Intel-Core-i7-8700K-Processor-12M-Cache-up-to-4_70-GHz

I would suspect that an "Intel-defined, high-complexity workload." would include AVX instruction set.
https://software.intel.com/en-us/articles/introduction-to-intel-advanced-vector-extensions/

If you were to run Prime95 with AVX instruction set then you would likely see a much higher power draw. You would also produce much higher temps, so be sure your cooling solution is adequate before you do that.

Prime95 Version 29.4 build 7 - https://www.mersenne.org/download/

 

[jojesa]

That should not be an issue for concern, since some dies are more efficient than others.
I had 65W CPUs that did not used more than 44W at full load and 95W that did not go above 80W.
That's low , so you could use Prime95 to see if it will remain around 50W.
Most users don't monitor CPUs that closely and that might be why we don't encounter this more often.

 

[volkgren]

I usually run Prime95 v26.6 because it does not use AVX instruction set, because most application and games do not use them either. Power draw on all Intel CPUs I've run ranging from Celerons, Pentiums, i3, i5, and i7 have all used considerably less power than the specified TDP running Prime95 v26.6.

 

[MattyG344]

Thank you all for the replies. It sounds like it's not necessarily something I should be fretting over, and since my cooler (Noctua NH-15) is doing a pretty good job keeping temps down I should be fine when it does run into something that taxes it. I'll run some stress tests that were suggested just in case, but I feel much better now, thank you!

 

[doverm]

I know this is kinda late to the party, but...why are you people insisting on that a i7-8700K is going to hold its TDP limit for power usage?
THG themselves have a review saying the consumption goes up to 116W, 133 with oc at 4.9Ghz, which is quite common. Using AXV lets it even suck up to 170Watts. The TDP is useless if you are going to run the cpu at full load, since it represents the power consumption at base speeds - which you dont really have while rendering, benchmarking etc.??

 

[volkgren]

I think the point being made (or that should be made) in this thread is that TDP isn't a very accurate or consistent basis for measuring power draw. It is meant to give the consumer an idea of the cooling solution required for normal operation.

 

[larrycumming]

Download and run the benchmark function of Intel XTU , extreme tuning utility

that will give you a pretty good idea of power draw

 

[mdd1963]

Power draw as shown in HWMonitor is simply the CPU quickly doing the math on what power draw should be for a given clock speed at a given core voltage under whatever type of load....(amps x volts = watts)

It's often something many folks waste time trying to 'fix', thinking power draw should be a constant 65 or 91 watts, etc...it can be more (many 7700K-8700K CPUs draw 135-140 watts under an overclocked heavy load) or less, depending on load.

If you are seeing the CPU ramp up to and maintain max turbo , w/ temps in check, then enjoy, and play!